Envelope moistening devices are well known. U.S. Pat. No. 4,903,633 illustrates an example thereof, with, disposed from upstream to downstream with respect to the direction of advance of the envelopes, a separator for separating the flap from the body of the envelope and a moisture applicator, placed just behind this separator, for moistening this flap once this flap is separated from the body of the envelope. This moisture applicator is preferably formed in two parts, with an applicator element whose end rests on a pad partly immersed in a reservoir of water disposed beneath the conveyor table, the flap being moistened during its passage between the applicator element and this moistened pad.
However, this moistening device suffers from several limitations due in particular to its moistening member. Firstly, its dimensioning prevents the passage of envelopes whose flaps exceed the width of the moistening member proper, conventionally of the order of 4 or 5 cm. Secondly, the nature of its material, composed of bristles and cellular material, is particularly subject to wear and tear and obliges regular changes, otherwise moistening is partial and non-homogeneous. Finally, without a complementary masking element for example, the very arrangement of the moistening member does not allow the passage of envelopes with open flaps without necessarily moistening the flaps thereof.
It is therefore an object of the present invention to provide a moistening device capable of moistening envelopes of different formats and types. The invention proposes producing such a device simply and inexpensively, minimizing the modifications to be made to a standard mail handling machine.